The National Agricultural Statistics Service reported that the U.S. produced the largest wheat crop since 2008-09, with 2.31 billion bushels. This is a 13% increase from last year and 10% above the five-year average yield. The following is an overview of how growers described this past season in wheat fields across the Dakotas:

WHEAT CROP: Wheat is harvested in North Dakota. (Photo: Syngenta)

Kochia
The biggest weed issue growers saw was the increase of kochia. It isn’t known if it was a change in product use (i.e., going from name-brand herbicides to generic products/ALS inhibitors) or due to herbicide resistance. There are two sides to this weed control story — did growers go cheap on their herbicide package, or did the weeds develop a tolerance to the product? If growers wait until herbicide resistance is confirmed in their fields, it may become more difficult to manage their weeds. Waiting for resistant weed populations to appear can cause herbicide resistance to spread faster across an entire field. Different fields demand different treatments. To maximize weed control, it’s important to know which product fits best. Limiting resistance starts with anticipating or recognizing the issue in the field by evaluating the plants that survive a herbicide application, and managing these weeds escapes to prevent an increase in next year’s weed seed bank.

GETTING CLOSER: Symptoms of stripe rust show up on wheat leaves. Stripe rust arrived earlier than expected in the region. (Photo: Syngenta)

Stripe rust
Stripe rust epidemics have been rare in the Dakotas, but the disease has increased since 2011. Stripe rust was found earlier this year than the year before, and the fungus was more widespread than even the year before that. Stripe rust is not the type of disease that shows up and then goes away. In April, stripe rust was found in Miller, S.D., only 100 miles away from the North Dakota border. Current understanding of how far north stripe rust can overwinter might not be correct. This may have to do with the fact that the Dakotas had a mild winter, or perhaps there is a new population of the pathogen. When selecting a fungicide package, growers should purchase a package that contains triazoles, strobilurins or mixed modes of action to protect against stripe rust. Timing of the application is key to getting good control.

Insects
There were also reports of wheat streak mosaic virus (WSMV) in spring wheat, meaning wheat curl mite may not only be attacking winter wheat, but may also be finding its way into spring wheat fields. Yield loss is dependent on the growth stage at the time of the infection, temperature and moisture. The unfortunate side of this is there are no chemicals currently on the market to manage the mite or virus directly. Growers should destroy all volunteer wheat plants and grassy weed hosts before planting wheat, and they should plant at the recommended seeding dates.

There continue to be many questions on wheat stem sawfly as well. This is another insect in the same category as WSMV. There is no good way to control this insect. Growers should be attuned to the presence of wheat stem sawfly because it bores into the joints of straws, which weakens and breaks them. The best way to combat this insect is to plant a certified seed variety with tolerance to sawfly.

Another key insect that growers are seeing in pockets of their fields is wireworm. Growers should continue to pay attention to this insect, especially in fields that were put into production after being in sod or long-term legumes, and in grass-cropped fields and reduced-tillage fields, as it is a multiyear pest. Growers should request thiamethoxam in their seed treatment package to suppress wireworm and other insects.

Vomitoxins
North Dakota recorded high levels of vomitoxin in durum and spring wheat in the northern part of the state. Some growers had fields that were completely burned to the ground. Growers who produced a wheat crop with vomitoxin saw a large price discount at local elevators, and some were even turned away. High humidity and moisture can create the perfect conditions for this fungus.

Next year, be sure to choose a variety with some resistance or tolerance to fusarium. It is also important to use certified seed. Vomitoxin does not come from seed, but seed containing high levels of vomitoxin may have germination and vigor problems. Treating seed with fludioxonil will help protect it against certain soilborne and seedborne diseases that could further stress the seedlings.

During the growing season, monitor the weather and growth stage of wheat. Be ready to apply fungicide if conditions warrant. A properly timed fungicide application can provide the plant with some protection against the fungus.

An integrated management approach will help boost crop productivity and grow profitable wheat.

Popiel is the Syngenta agronomic service representative in North Dakota. Contact him at [email protected].